Effectively Communicating Heat Stress Using Wet Bulb Globe Temperature and the North Carolina Environment and Climate Observing Network

Extreme heat is the deadliest weather hazard in the US. Weather forecasters rely on heat risk metrics, such as heat index, to anticipate and communicate risk during heat events. While heat index is a more common metric of heat stress, wet bulb globe temperature (WBGT) is becoming a metric many groups, such as the Occupational Safety and Health Administration (OSHA) and North Carolina High School Athletic Association, use to describe heat stress. WBGT takes into account solar radiation and wind speed, along with air temperature and relative humidity, to better represent heat stress on the human body while outdoors. Though WBGT may better represent heat stress, communicating risk with the WBGT temperature scale is a challenge. WBGT temperature scale values are typically lower than air temperature or heat index, making it difficult to convey to the public that a value is significantly worse for your body than that same air temperature. Alternate WBGT communication approaches have used a categorical scale to improve interpretation (e.g., low, elevated, moderate, high, extreme), similar to severe weather or drought monitoring. Furthermore, accurate observations of WBGT are sparse due to the need for specific equipment to measure black globe temperature, a key component in the WBGT calculation. The North Carolina Environment and Climate Observing Network (ECONet) is a network of research-grade weather stations located throughout the state operated by the North Carolina State Climate Office (NCSCO), which collects measurements of a number of environmental parameters, including black globe temperature. The NC ECONet is one of the only state networks to observe and record these data. The ECONet provides real-time WBGT values across the state on a 1-minute timescale. Using these data, we are able to showcase ECONet-powered WBGT communication tools that provide current WBGT conditions and measure accumulated hours by WBGT category, which may improve WBGT communications. Using these custom products, we work with local partners (e.g., Cooperative Extension, the National Weather Service, State and Federal Parks). We employ different communication tools (alerts, social media, email listservs) to better warn stakeholders of heat emergencies and provide information on what to do during extreme heat events.